It's going to be for sure weaker than Domain Invasion gear stats, but that should honestly be the floor. -50% DT, +150 Magic Evasion (30 per main armor slot, can't go too crazy), similar evasion, +30 MDB, and requisite defense.
I honestly don't even know why any of this is necessary. Just press one button and make Moogle Mastery global, and there's your trust gear. MM45 AAEV+Ygnas pair can survive a full 8 minutes between the two of them on v25 Ongo (with SCH Regen), and this was before trust updates. If MM could be paired outside of Gaol with current primer stat buffs, you wouldn't need gear at all. Not sure why they're going this route when the infrastructure is already there (I suppose new players might struggle to increase Moogle Mastery rank, but don't you want new players doing Sheols since it's the next step up in content anyways?). Just weird
I do, however, wonder how strong trusts can get with this new attachment/gear inside Gaol. Seems redundant of an update to me though.